People like to watch television on the go and when away from home. For example, people who travel by recreational vehicles (RVs) and camping trailers desire to watch broadcast television either while in transit, or while at their destination. Such persons typically have two options for viewing television programming, off-air (over-the-air terrestrial broadcast) and satellite broadcast reception.
Off-air television signals are transmitted from earth-based transmitters over the VHF and UHF frequency bands. These transmitted, sometimes called “off-air”, signals remain popular because the programming transmitted by these signals is free to view. In contrast, most television transmitted via satellite transmission requires payment of a subscription fee to view the transmitted programming. Off-air antennas also allow the user to receive local programming at a destination that corresponds to that destination, whereas satellite broadcasts contain local programming for only one location regardless of where the user is physically located. Sometimes purchasers of satellite transmission services supplement their subscription services with off-air reception in order to receive local programming that is not available or is sold for additional fees by the subscription service provider. This supplementation is becoming particularly prevalent with the 2009 switchover from analog to digital terrestrial television signals in the United States.
Signal strength received from terrestrial transmitters weakens as the distance away from the transmitter becomes greater. At a certain distance from the transmitter, the signal will become too weak to be viable. For analog television signals that are too weak, the picture on the television appliance will become fuzzy or snowy if it can be received at all. For digital television signals, no picture will display on the television if the signal is too weak. Off-air antennas are usually mounted on the rooftop of a recreational vehicle (RV), camping trailer, or the like, in order to afford the best reception. One example of a roof-mounted off-air antenna for RVs is disclosed in U.S. Pat. No. 5,262,793.
Mounting an antenna outside of the vehicle lessens interference from electronics and a roof-mounted outdoor antenna is less likely to receive reflected ghost signals from the vehicle structure. In addition, mounting an antenna higher above the ground increases the amount of direct signal it can receive from a transmitter.
The antenna mounted on the roof is connected to one or more television appliances in the vehicle using, for example, coaxial cable lines and splitters routed throughout the vehicle structure. Reception can be improved for directional antennas by aiming (e.g. rotating) the antenna towards the source of the broadcast signal. The source direction can be different for different channels due to different locations of the respective broadcast towers for each channel.
Conventionally, the user is provided with an antenna adjustment mechanism inside of the vehicle cabin. The user typically scans for channels using the television appliance, and then rotates the roof-mounted antenna if the desired channel is not located. Following a rotation, the user performs another scan on the television to see if the desired channel is located. If not, a further rotation and scan is performed. This process is repeated until the desired channel is located or the user gives up trying to find the desired channel. If the channel is located, then the user can use a signal meter function built into the television appliance, if one exists, to tune or peak the signal strength by making adjustments to the antenna position while observing the television appliance. Some television appliances do not have a meter function. As can be appreciated from this description, the conventional method of locating television channels involves considerable guesswork. The user typically does not find the peak, or strongest direction, of the signal using the conventional method. Even if the television appliance decoder has the ability to display a signal meter on the television screen, the user may not be able to see it. Therefore, there is a need for an improved antenna system that allows a user to quickly and easily aim an off-air antenna.